diff mbox

[U-Boot] exynos5: Don't potentially undervoltage the CPU

Message ID 20170110112857.30074-1-sjoerd.simons@collabora.co.uk
State Accepted
Commit 701e740f59bb1108485f1cb8e1b54248eee3ff87
Delegated to: Minkyu Kang
Headers show

Commit Message

Sjoerd Simons Jan. 10, 2017, 11:28 a.m. UTC
For snow when chainloading u-boot the CPU seems to be running at full
speed. The lower CPU voltage seems to be ok for u-boot, but when booting
linux (bringing up all cores) I'm seeing random crashes.

Bump the voltage up to a level that's safe for all cpu frequencies.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>

---

 board/samsung/common/exynos5-dt.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

Comments

Javier Martinez Canillas Jan. 10, 2017, 12:21 p.m. UTC | #1
Hello Sjoerd,

On 01/10/2017 08:28 AM, Sjoerd Simons wrote:
> For snow when chainloading u-boot the CPU seems to be running at full
> speed. The lower CPU voltage seems to be ok for u-boot, but when booting
> linux (bringing up all cores) I'm seeing random crashes.
> 
> Bump the voltage up to a level that's safe for all cpu frequencies.
> 
> Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
> 
> ---
> 

Your patch looks good to me, 1.3V matches the operating point defined
in the Exynos5250.dtsi for the maximum CPU frequency (1.7 GHz).

Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>

Best regards,
Minkyu Kang Jan. 18, 2017, 5:21 a.m. UTC | #2
On Tuesday, 10 January 2017, Javier Martinez Canillas <
javier@osg.samsung.com> wrote:

> Hello Sjoerd,
>
> On 01/10/2017 08:28 AM, Sjoerd Simons wrote:
> > For snow when chainloading u-boot the CPU seems to be running at full
> > speed. The lower CPU voltage seems to be ok for u-boot, but when booting
> > linux (bringing up all cores) I'm seeing random crashes.
> >
> > Bump the voltage up to a level that's safe for all cpu frequencies.
> >
> > Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk
> <javascript:;>>
> >
> > ---
> >
>
> Your patch looks good to me, 1.3V matches the operating point defined
> in the Exynos5250.dtsi for the maximum CPU frequency (1.7 GHz).
>
> Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com
> <javascript:;>>
>
> Best regards,
> --
> Javier Martinez Canillas
> Open Source Group
> Samsung Research America
> _______________________________________________
> U-Boot mailing list
> U-Boot@lists.denx.de <javascript:;>
> http://lists.denx.de/mailman/listinfo/u-boot
>

 applied to u-boot-samsung

Thanks
diff mbox

Patch

diff --git a/board/samsung/common/exynos5-dt.c b/board/samsung/common/exynos5-dt.c
index 2e3b16df45..aec1f396b0 100644
--- a/board/samsung/common/exynos5-dt.c
+++ b/board/samsung/common/exynos5-dt.c
@@ -123,13 +123,7 @@  int exynos_power_init(void)
 	if (ret)
 		return ret;
 
-	/*
-	 * This would normally be 1.3V, but since we are running slowly 1.1V
-	 * is enough. For spring it helps reduce CPU temperature and avoid
-	 * hangs with the case open. 1.1V is minimum voltage borderline for
-	 * chained bootloaders.
-	 */
-	ret = exynos_set_regulator("vdd_arm", 1100000);
+	ret = exynos_set_regulator("vdd_arm", 1300000);
 	if (ret)
 		return ret;
 	ret = exynos_set_regulator("vdd_int", 1012500);